Vortex Separator for Downhole Motor Bearing Protection
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Solution Overview
Problem
In abrasive wellbore environments, electric submersible pumping systems face reduced motor protector run life due to wear from abrasive sand, which existing designs fail to adequately address, particularly in journal bearings.
Innovation Solution
A vortex fluid separator and filter system is employed to separate solids and water from reservoir oil, using a porous filter as a secondary filter to ensure continuous flushing of bearings with filtered wellbore fluid, and a screw or gear pump to energize the flushing fluid, maintaining pressure balance and preventing solids from entering the motor rotor cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If journal bearings are made from extremely hard materials to reduce wear from abrasive sand, then wear resistance is improved, but the complexity of the motor protector increases
Solution Approach 1:
The vortex separator and filter system performs preliminary separation and filtration of sand and solids from the motor oil before the oil reaches the journal bearings. This prevents abrasive particles from causing wear, eliminating the need for extremely hard bearing materials and reducing overall system complexity while maintaining reliability
Solution Approach 2:
A porous filter medium acts as an intermediary between the motor oil and the journal bearings, selectively allowing oil to pass through while blocking sand and solids. This intermediary protection mechanism resolves the contradiction by providing wear resistance through filtration rather than through hard bearing materials
2Reliability
If a vortex separator and filter system is added to separate solids from motor oil, then reliability is improved, but device complexity increases
Solution Approach 1:
The motor oil serves multiple functions: it provides lubrication for the journal bearings, acts as a carrier for the vortex separator to remove solids, and functions as a flushing medium. By making the oil multi-functional, the system achieves improved reliability through solid separation without proportionally increasing complexity
Solution Approach 2:
The system uses the motor's own operating oil to perform the separation and filtration function, rather than requiring an external cleaning system. The oil circulates through the vortex separator and filter, automatically removing solids during normal operation, which improves reliability while minimizing additional system complexity
3Reliability
If the motor rotor cavity is pressure balanced with filter medium that allows fluid entry and exit but blocks solids, then reliability is improved, but device complexity increases
Solution Approach 1:
A porous filter medium, which can be implemented as a thin film or membrane, is used to balance pressure between the motor rotor cavity and the external environment while blocking solids. This thin film approach provides effective protection without adding significant structural complexity to the motor protector design
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively extends motor protector run life by preventing sand and solids from entering the rotor cavity, ensuring continuous lubrication and pressure balance, thereby enhancing motor and pump bearing reliability and performance.
Implementation Method 1
a vortex separator is used separate the solids and water from the reservoir oil
Implementation Method 2
The vortex separator rotates with the shaft. The vortex separator has an outer wall that has a funnel-shaped portion... as fluid and suspension mixture is introduced into the vortex separator from the chamber, the separator draws and separates the solids and water
Implementation Method 3
a porous filter means is used as a secondary filter... the filter medium which allows fluid to both enter and leave the rotor cavity but no solids can enter the rotor cavity
Implementation Method 4
A screw pump is used to boost the pressure of the flushing oil to be equal to the pump discharge pressure
Implementation Method 5
Discharge at each bearing is regulated by a combination of the external pressure at that point and a flow control device such as a Lee Viscojet
Data Source
AI summary
A separator for reducing or eliminating the amount of suspending solids from a reservoir fluid of a downhole motor having a rotating seal. The cleaned fluid circulated past the seal and outermost bearing, the separator having a vortex, rotating cyclone or centrifuge, at least one inlet at least one outlet for cleaned fluid, at least one outlet for solid material, water, particulates or similar material separated from the cleaned fluid. The outlet for the clean fluid may include a porous filter.